1. Field of the Invention
The present invention relates to filter devices, and in particular, to filter devices for filtering foreign substances e.g. iron oxides which may be contained in water supplied to an apparatus, such as a washing machine.
2. Description of the Prior Art
It has recently been proposed to provide a washing machine with separate washing and dehydrating tubs for respective washing of fabric articles on the one hand and for rinsing and dehydrating the fabric articles on the other hand. When using washing machines of this type in geographical areas where the water supply is contaminated or contains impurities, the washed articles may become discolored by iron oxide powder or other foreign matter contained in the water supply when the contaminated water is supplied to the dehydrating tub for rinsing the washed fabric articles. Therefore, washing machines intended for use in those geographic areas where the water supply is impure must be provided with a filter for filtering the water supplied to the dehydrating tub. Normally, the water filters are provided structurally independently of the washing machine.
Conventional water filters include a housing formed with a cylindrical hollow body opened at its top end and a lid member as can be seen by reference to published Japan Patent Application No. 57-173806. The lid member closes the open top end of the cylindrical hollow body in a water tight manner. A cylindrical hollow filter medium is then concentrically disposed in a loose-fitting relationship within the cylindrical hollow body. The cylindrical hollow filter medium partitions the interior of the cylindrical hollow body into substantially concentrically oriented discharge and intake chambers. Water from the water supply is thus introduced into the intake chamber, and then forcibly discharged into the discharge chamber through the cylindrical hollow filter medium by means of the water supply pressure.
In the above construction (typically referred to as a closed-type filter), the housing of the filter is made of steel so that it can better withstand the pressure of the water supply. Therefore, such filters are relatively more expensive owing to their steel construction. Moreover, the lid member of the conventional filter is not easily openable except with the use of special tools when a user intends to clean the cylindrical hollow filter medium contained therein.